A/n: Nothing could stop Sirius Black from loving Y/n L/n, a curse, a sacrifice, death. He would do absolutely anything for the two of them to be together forever; Immortal!reader
3rd POV:
To most everyone, Y/n was a young 7th year Ravenclaw, studying at Hogwarts in 1978. She was exceptionally smart, there was no denying that, and utterly beautiful. She was able to stay under everyone's radar, just minding her business, but she could never escape Sirius.
The two knew each other since they were children, while Sirius was apart of the House of Black and the Sacred 28, the L/n family was famous in another way. It was secret kept between the 29 families. Back in the 13th century, a witch had fell in love with Percival L/n, but had been infatuated with other. The witch had been filled with green and placed a curse on the family, any first born coming from the L/n family would be cursed with immortality, immune to the ravages of time, never aging past the age of 20.
Y/n was the first born and the only child of Richard and Maria L/n. Despite the curse, she lived a wonderful childhood, living it to the fullest. Her aunt, her mother's older sister, was the first born and she grew up listening to the stories of her aunt's lovers. Her parents tried their best to help her with the curse, but there was so much they could do, they weren't cursed with immortality, they could live and love and grow old together.
The L/n daughter didn't want an epic love, she didn't want to devote her heart to someone, only to watch them grow old while she stayed at the age of 20. Sirius had been in love with her since they were children, it was no secret. In some ways, Y/n did reciprocate the feelings, the two had chemistry. But Y/n didn't want to give into the power of love, she didn't want to watch him grow old while she stayed young.
Like clockwork, Sirius joined her at the top of the Astronomy Tower. At this point, he didn't even need to think about it, he would just let his feet take him up there. He saw sitting at the edge, feet dangling, her arms on the railing, looking up at the sky.
"Which one is Sirius again?" She asked. Now, she knew where it was, she knew since she was a girl, but like Sirius, she didn't even think about it, it was like second nature asking that question.
"Right there." He grabbed her hand with his and guided her towards star. "You know Sirius is the brightest star in the night sky as seen from Earth?"
"Really?" She said impressed, despite being named after a star, Sirius never got into Astronomy.
He just nodded and sat down next to her wrapping an arm around her shoulder. "Do you ever think about what you'll do once you graduate?"
"I want to get a good job, maybe something with Astronomy, a professor of some sorts. I could work for a few years and by the time I turn 30, I either leave London and change my identity or be confined to my house for the rest of eternity." Y/n explained. She had about another good 10 years left before she would have to make a choice, fight or flight. Her aunt had chose flight, every 10 years she would change her identity, and move somewhere new. Y/n didn't know what to choose yet.
"Don't you miss having someone to love?" He asked.
"It's not the same when there's no growing old together." Y/n smiled sadly.
It was like Sirius's heart broke again. How he wished he could do something to help her, but it was no use. For centuries, the L/n family had been looking for a cure to take away the immortality. Eventually the first borns would die, because even with magic and curses, immortal being can find a way to die.
"If there would be anything to keep you here, what would it be?" Sirius asked.
Y/n took a few minutes to think, the one thing that would keep her here. "You."
"Me?" Sirius questioned. It wasn't the answer he was expecting. "You would stay for me?"
"I would." She replied. "I think there's some part of me, wanting to stay with you forever, and if I could given the chance, I would. But the gods play favorites, and I wasn't one of their favorites."
Sirius didn't need an 'I love you' from her, that was enough. Knowing she would stay with him if the circumstances were different, that was the equivalent of an 'I love you'.
"What if we didn't need a chance." Sirius told her.
"Sirius what do you mean?" She furrowed her brows looking at him.
"There must be a may for someone to be immortal, the Dark Lord did it, you take apart of your soul away." Sirius explained.
"No, Sirius, no. I can't let you do that." Y/n said frantically.
"Why not, you just said you would be with me, if you could. Now I'm giving you the chance, I rather not age another day knowing we could be together." Sirius pleaded.
"You can't do that, you have your friends to think about." Y/n said. She knew James, Peter, Remus and him were friends since they were 11, they were his brothers.
"If they were in my situation, they would give themselves up for love." Sirius ran his fingers through his hair.
"You would get lonely, I don't want kids, I don't want one of them going what I went through. I want to end my bloodline." Y/n explained.
"Then we can end our bloodlines together." Sirius argued. It was like for whatever negative though Y/n tried to put through his head, went in one ear and out the other.
"Why must you do that?" She asked.
"Do what?" Sirius asked trying not to lift the corners of his lips up.
"Whenever I try to get you to leave, you find another reason to stay." Y/n exclaimed.
"Don't you get it." He grabbed her hands. "No matter what you say, not matter the consequences, I'll always be here. I want to be with you, I want us to be together, I'm willing to give apart of my soul away so we can immortal together. So get it through your hard head that I love you."
"You were always stubborn." Y/n laughed quietly wiping her tears away. "Always have to get what he wanted."
"Am I getting what I wanted right now?" He asked hopefully.
"Yes." Y/n looked up at him. "We can be together forever."
Sirius laughed through his tears, cupping her face and smashing his lips onto hers. It was their first kiss, but it certainly wouldn't be there last.
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